Method for coating an object by means of a multilayer system with a nickel-phosphorus alloy

Abstract

A method for coating an article, wherein a surface of the article is at least partially coated with a coating that has a multiplicity of layers, wherein at least one layer of the coating is made of a nickel phosphorus alloy and wherein a mass fraction of the phosphorus in the nickel phosphorus alloy is at least 8%.

Description

[0001]This nonprovisional application is a continuation of International Application No. PCT / EP2017 / 000498, which was filed on Apr. 19, 2017, and which claims priority to German Patent Application No. 10 2016 004 913.8, which was filed in Germany on Apr. 22, 2016, and which are both herein incorporated by reference.BACKGROUND OF THE INVENTIONField of the Invention[0002]The present invention relates to a method for coating an article using a multilayer system. Such multilayer systems are used as corrosion protection and / or as decorative coatings, for example. In particular, the intent is for articles of sanitary facilities, such as, e.g., plumbing fixtures, to be produced or finished using the method specified here.Description of the Background Art[0003]Multilayer systems based on electrochemically deposited metal layers can produce corrosion products as a function of the employed substrates, layer materials, surrounding media, and reaction conditions. Moreover, the process of corros...

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Benefits of technology

[0022]Another very particular advantage of the invention is achieved when the chromium layer is applied directly on the nickel phosphorus alloy. The corrosion resistance of the chromium layer is especially improved by this means. If, in addition, a chromium layer made of a trivalent chromium electrolyte is applied electrolytically on the nickel phosphorus alloy, it is particularly also possible with this electrolyte to achieve especially good corrosion resistance, which is substantially better than previously known coatings of trivalent chromium. These advantages are achieved through the direct combination of the nickel phosphorus alloy with the chromium layer applied thereon. This combination can be used in different locations within the framework of a layer structure according to the invention, and can achieve the previously described positive technical effect there. Thus, the layer pairing can also be used in the advantageous manner as, for example, a first and second layer or as a second and third layer of a layer structure.

[0023]In addition, it is advantageous if a brush structure is introduced in the coating. The application of a brush structure is generally carried out in conjunction with the above-mentioned PVD coating. The resulting final surfaces are “brushed stainless steel” or “brushed nickel,” for example. The brushing is carried out by pressing the articles against rotating disks. These disks may be polishing disks with suitable polishing pastes, fiber brushes, or sisal brushes, for example. This step is carried out before PVD coating, or even before the chromium plating.

[0024]Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

Problems solved by technology

Moreover, the process of corrosion depends on geometric circumstances (for example, resulting in crevice corrosion) and mechanical influences (for example, friction).

Damaged chromium coatings, but also coatings with chromium layers that are not fully continuous, that were deposited too thinly, or that are porous, soon (depending on external conditions such as usage, cleaning, and surrounding media) result in corrosion products that are visually unsightly, and can lead to component failure in susceptible substrate materials.

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